loader.conf: add LinuxKPI based wireless drivers to module_blacklist

Despite being discouraged in the man page people are trying to load
the driver from loader.  In that case firmware is missing and the
root file system is not there yet and the LinuxKPI based drivers
will panic the system on boot.  Simply avoid any further support
trouble by disallowing them to be loaded from loader.
If someone still wants to do it, they will need to figure out how
to remove them from the blocklst and how to loader the firmware
file(s) in advance themselves.

Sponsored by:	The FreeBSD Foundation
MFC after:	3 days
PR:		287480
Reviewed by:	imp
Differential Revision: https://reviews.freebsd.org/D50817

stand/defaults/loader.conf

@@ -111,7 +111,7 @@ kernels_autodetect="YES"	# Auto-detect kernel directories in /boot
 #console="vidconsole"		# A comma separated list of console(s)
 #currdev="disk1s1a"		# Set the current device
 module_path="/boot/modules;/boot/firmware;/boot/dtb;/boot/dtb/overlays"	# Set the module search path
-module_blacklist="drm drm2 radeonkms i915kms amdgpu"	# Loader module blacklist
+module_blacklist="drm drm2 radeonkms i915kms amdgpu if_iwlwifi if_rtw88 if_rtw89"	# Loader module blacklist
 #prompt="\\${interpret}"	# Set the command prompt
 #root_disk_unit="0"		# Force the root disk unit number
 #rootdev="disk1s1a"		# Set the root filesystem